Gas distribution is often done through underground pipes. Due to the severity of the possible effects of leaks and the generally inaccessible nature of the pipes, various methods have been devised for checking for such leaks. Currently, the most predominant method involves driving a long metal rod or probe (often ⅜″ to ½″ in diameter) into the ground.
Driving the rod into the ground can prove to be difficult. As such, driving the rod into the ground can be accomplished using a sliding weight that impacts a fixed collar on the rod. The user lifts the weight and slams it down onto the collar, creating the force necessary to drive the rod into the ground. This is repeated to achieve the desired depth. Other methods can also be employed which rely on creating a downward force on the rod sufficient to drive the rod into the ground. For example, a small (5 lb.) sledge hammer can be used to drive a hardened bar into the ground.
Depending on conditions, removing the rod can prove more difficult than initially driving the rod into the ground. This is particularly true where the rod is driven into asphalt or other dense materials. It is also sometimes made difficult when the ground is frozen as the bar tends to heat during insertion, thus melting water in the surrounding soil, which can subsequently freeze the bar into the ground. Bars that prove difficult to remove, or “stuck” bars are often removed through two methods. First, the weight used to pound the weight into the ground may be used in a reverse motion. The weight can be lifted and hit against the collars on the rod, thus using the weight in an upward motion. Secondly, a lever device can be used.
At present, the levers used generally have “teeth” that slide onto and grip the bar. A lever will also have a pivot point approximately 6-8 inches away from where the teeth grip the bar. Handles extend from the device for approximately 48 inches from the pivot point. To use the lever, a user would position the teeth so as to grip the bar appropriately, and then the user can grip the end of the handle with his or her hands and push down. This action creates an approximate 6-1 or 8-1 mechanical advantage, which in turn creates enough lifting force on the stuck bar to lift it at least partially from the ground.
Although this lever method generally works for most stuck bars, it can be hard on the user. In order to properly work a lever for this purpose, the user must flex his or her torso and bend down to create the necessary downward force. This bending motion is not good biomechanical loading on the body and may have negative immediate and/or long-term effects.
Additionally, current levers are often heavy and may further cause strain on a user for initially positioning the lever near the stuck rod, and returning the equipment. Further, some currently used levers prove awkward in handling in that they may require the user to exert time and effort in properly setting-up the apparatus and in maintaining balance of the tool.